Steady bearing assemblies for non-metallic, vertical sump and process pumps are normally lubricated by a clean external source of liquid, usually water, or by delivery of product being pumped through a piping system from the pump's discharge. Steady bearing assemblies for metallic, vertical sump and process pumps are also normally lubricated by a clean external source or by product flush. A clean external source of cooling liquid, such as water, requires a delivery piping system and a control system to shut off the liquid when the pump is not running. Some of these metallic pumps employ a sealed bearing assembly that includes a bearing lubricated by grease introduced through external tubing. The grease is retained in the bearing by lip-style grease seals. Heat generated by the grease seals and by churning of the grease is carried away from the bearing through convective and conductive heat transfer through the metal housing and column pipe preventing excessive temperatures.
Both of these designs have inherent equipment, material, installation, and maintenance costs. For example, water lines installed in climates where the ambient temperature drops below freezing must be protected from freezing or the pump installed indoors which increases installation costs. If the liquid is not turned off, and continues to drain into the sump, the liquid will eventually have to be pumped out of the sump and treated which adds to maintenance costs. Product-flush bearing lubrication requires that the product be relatively clean, although sump applications can contain abrasive particles which can accelerate wear of the bearings and necessitate repeated and costly replacement. Various chemicals can be collected in waste sumps. If the chemicals are corrosive, e.g., hydrochloric acid, sulfuric acid, etc., the bearing assemblies must be fabricated using noble alloys to withstand the effects of these chemicals and yield a reasonable pump life. Noble alloys, such as Hastelloy B or C, Titanium, etc., can be very expensive and have long lead times as compared to non-metallic materials that can withstand the same chemicals.
Accordingly, there is a need for a steady bearing assembly that is less costly to build, install and maintain than conventional steady bearing assemblies.